Rayleigh Scattering Measurements in NASA Lewis Wind Tunnels

Two applications of Rayleigh scattering for measuring flow parameters in wind tunnels are described. The first is the measurement of one velocity component and static temperature in the vicinity of a 12 % scale advanced short takeoff and vertical landing (ASTOVL) aircraft model in the Lewis 9 ft by 15 ft low speed wing tunnel. The model was equipped with high temperature and high pressure air supplies to simulate lift nozzles and suction systems to simulate engine inlets. The second application is a feasibility study to measure flow properties in a 4 inch by 10 inch supersonic wind tunnel This technique uses an injection seeded, frequency doubled Nd:YAG laser tuned to an absorption band of iodine.